Epicyclic weaving of fiber discs

ABSTRACT

An apparatus for winding one or more fibers under tension onto a former is used for making a turbine or compressor rotor for a gas turbine engine. The apparatus includes an epicyclic system having an annulus wheel means and at least one planet wheel means which can be rolled about a circumference of the annulus wheel means to define an epicycloid path of travel. A guide means is operatively associated with one of the planet wheel means for guiding one or more fibers from a source of supply onto a former, and the guide means is arranged so that its end nearer the former follows a substantially epicycloid motion as dictated by the rolling of the planet wheel means about the circumference of the annulus wheel means.

United States Patent 1191 Palfreyman et al.

[ EPICYCLIC WEAVING OF FIBER DISCS [75] Inventors: Jack Palfreyman,Tansley, Nr. Matlock, Derbyshire; Henry Edward Middleton, Derby; AlanAnthony Baker, Mickleover, Derby, all of England [73] Assignee:Secretary of State for Defence, London, England [22] Filed: March 13,1970 [21] Appl. No.: 24,404

Related U.S. Application Data [62] Division of Ser. No. 735,411, June 7,1968, Pat. No.

[ March 6, 1973 Primary Examiner-James Kee Chi Attorney-Cushman, Darby &Cushman [57] ABSTRACT An apparatus for winding one or more fibers undertension onto a former is used for making a turbine or compressor rotorfor a gas turbine engine. The ap- 3,632460 paratus includes an epicyclicsystem having an annulus wheel means and at least one planet wheel means52 U.S. c1. ..28/l5 28/2 242/1 which can be mlled a cirwmference 0f the51 1111.0 .jmmc 3/08 wheel means define Path [58] Field of Search 28/152 1 139 I3 travel. A guide means is operatively associated with 23/46 3l56/169 one of the planet wheel means for guiding one or more fibersfrom a source of supply onto a former, and the guide means is arrangedso that its end nearer the former follows a substantially epicycloidmotion as r [56] References cued dictated by the rolling of the planetwheel means UNITEDSTATES PATENTS about the circumference of the annuluswheel means. 2,061,654 11/1936 Goff et al ..28/l5 x 5 Claims, 6 DrawingFigures 2,152,373 3/1939 Bronson et a1 ..156/l72 X PATENTED IA R BISTZ,

sum .3 or 4 EPICYCLIC WEAVING F FIBER DISCS This is a division ofapplication Ser. No. 735,411 filed June 7, 1968, now U.S. Pat. No.3,682,460 issued Jan. 4, I972.

The present invention relates to turbine and com pressor rotors for gasturbine engines and includes a method of making such rotors bothseparately and with integral blades thereon.

Although the following descriptions and accompanying drawings relate tovarious methods and products, the primary objective of this applicationis to describe and claim an apparatus for producing certain products inaccordance with the methods which are described below.

According to one aspect of the present invention a turbine or compressorrotor for a gas turbine engine comprises a single continuous fiber or acontinuous bundle of fibers woven between points on the circumference ofthe rotor said points lying on opposite sides of the center of the rotorand the fiber or bundle of fibers passing adjacent to the circumferenceof an aperture at the center of the rotor between said points. The rotorrim may have increased thickness in order to anchor the fibers and toprovide means for attaching blades to the rotor.

A continuous fiber is meant to include a fiber in which two ends havebeen joined by an overlapping joint in which the length of overlap is atleast fiber diameters.

According to another aspect of the present invention method of making aturbine or compressor rotor for a gas turbine engine, comprises thesteps of weaving a single continuous fiber or a continuous bundle offibers on to a former in a plurality of passes between points on thecircumference of the former, and on opposite sides of the centerthereof, the fiber or bundle of fibers passing adjacent tothecircumference of an aperture at the center of the rotor between eachtwo points. The fiber may be anchored at the rim of the former byproviding additional material to thicken the rim.

The fibers are preferably held in tension throughout the weaving processand are also preferably coated with either a synthetic resin material ora metallic material.

Furthermore the fibers may be given an additional coating during theweaving process, which coating serves to hold the fiber in place.

In the application of the invention to a compressor rotor which operatesat relatively low temperature the coating on the fiber may be athermosetting resin, for example epoxy, polyimide, polyquinoxaline,

-polythiazole, polybenzimidazole resins or a ladder polymer.

In the application of the invention to turbine rotors which operate atrelatively high temperatures the fiber may be coated with a metal or ametal alloy, for example nickel, chromium, niobium, tantalum or an alloyof nickel and chromium.

The fiber itself may be carbon, boron or silica.

In the case of metal coated fibers the fibers may be coated with metalduring an electrolytic process or alternatively the metal may be sprayedon in molten state, or vapor deposited.

The above described method lends itself to continuous production offibrous rotors and in one method of carrying out the invention thefibers are fed to a point on the circumference of a planet wheel of anepicyclic gear. On rotation of the planet wheel around the periphery ofthe annulus gear the point on the circumference to which the fiber isfed performs an epicycloid motion. During this motion the fibers may bewound around pegs disposed on the circumference of the former oralternatively the former may comprise a disc which has been previouslyetched with grooves of a substantially epicycloid shape.

The whole of the woven disc may be filled with a filler material, forexample a foamed ceramic in order to provide axial support for thefiber.

The method may be extended to the production of a rotor with integralblades by superimposing on the weaving motion a radial movement everytime the fiber reaches the circumference of the former. The resultingradially extending fiber portions form a reinforcing spine in a rotorblade.

In an alternative construction the integral blade and disc may be formedwith an integral shroud joining the blade tips by causing the weavingmechanism to move radially from the disc circumference outwards to forma flank of one blade and to then move circumferentially to the nextblade and finally to move radially inwards to the circumference of thedisc before performing the next pass across the disc.

The invention also includes a gas turbine engine provided with rotordiscs woven as described above.

The invention will now be described in more detail, merely by way ofexample, with reference to the accompanying drawings in which:

FIG. 1 illustrates diagrammatically a gas turbine engine to which theinvention may be applied,

FIG. 2 shows a disc made by the method according to the presentinvention,

FIG. 3 illustrates diagrammatically one type of machine for making discsaccording to the present invention,

FIG. 4 shows how a blade may be formed integrally with the disc,

FIG. 5 illustrates how an integral disc and blade may be provided withan integral shroud at the blade tip, and

FIG. 6 illustrates a finished blade with an integral shroud wovenaccording to the present invention.

Referring now to FIG. 1 there is shown a gas turbine engine 1 havingcompressor means 2, combustion equipment 3, turbine means 4 and a finalnozzle 5 in flow series. Both the compressor means 2 and the turbinemeans 4 of the gas turbine engine comprise rotor discs 6 on which aremounted a plurality of aerofoil shaped blades. One such rotor disc 6 isillustrated in FIG. 2 and comprises a plurality of fiber portions, 7 ofasingle continuous fiber or continuous bundle of fibers, which are wovenin tension betweensuccessive points on the circumference of the disc,the fiber portions passing adjacent to the circumference of a centralaperture 8 of the disc. In the particular weave shown in FIG. 2 thesuccessive points on the circumference on the disc lie on opposite sidesof the center of the disc, for example a fiber portion starting at thecircumference at point 0 extends across the disc adjacent to the centerapertures to a point b on the circumference on the opposite side of thecenter and then extends back across the disc adjacent to the centralaperture to a point 0 on the circumference on the opposite side of thecenter. From there the fiber extends to point d, and in this manner theweave is continued until the whole disc is formed.

By suitably choosing the number of points a, b, c, d etc it can bearranged for the weave to start and finish at the same point on thecircumference of the disc.

FIG. 3 illustrates diagrammatically one way in which the disc may bemade. The fiber is fed from a reel 21 to a point on the circumference ofa planet wheel 22 of an epicyclic gear. The planet wheel 22 is attachedby means of arms 23 to the driven shaft 24 of an electric motor 25 andon rotation of the shaft 24, the planet wheel 22 is driven round theinternal perphery of an annulus gear 26 so that the point on thecircumference of the planet wheel 22 to which the fiber is fed performsan epicycloid motion. From the planet wheel 22 the fiber is fed througha tube 27 to a former 28 on which are mounted a plurality of pegs 29around which the fiber is would. The former 28 is a flat disc having acentral circular projecting boss 30 and a plurality of pegs 29 mountedaround the periphery. By winding the fiber around the pegs 29 acontinuous tension may be applied to the fiber portions 7 of the discand the fiber portions will in this case be substantially straightbetween the pegs 29, and will also be substantially tangential to thecentral boss 30. The pegs 29 and the former 28 are initially coated witha releasing agent to aid removal of the finished rotor.

It may be desirable that the fiber portions 7 are curved, so that onrotation of the discs the resultant stress in the fiber portions is morenearly pure tension. This may be achieved by using the epicyclic gear toetch a continuous groove in the desired pattern on to a former and tosubsequently feed the fibers under tension into the groove in theformer.

The fibers are coated with either a thermosetting resinor a metal alloy,depending on the temperature of operation of the disc. The fiber on thereel 21 may have been pre-coated. In order to anchor the fiber portionsin position during the winding process the fibers are continuouslycoated as they are woven. In the case of resin coated fibers for lowertemperature operation the coating may be applied in the form of veryviscous liquid and the disc may be heated when complete to cure theresin. When the fiber is to be coated with a metal or alloy, for hightemperature operation, the whole weaving process may take place in a vatof electrolyte so that the fiber is individually coated and at the sametime continuous electrolytic deposition anchors the fiber portions whichhave been positioned on the former. Alternatively the disc may be woundand electrolytically plated when finished.

In order to complete the disc as shown in FIG. 2 a plurality ofcircumferentially wound fibers are provided at the outer periphery ofthe disc to thicken the disc to provide material for withstanding thehoop stresses produced in the disc during rotation thereof and to anchorthe fibers. In the case of electrolytically coated metal fibers thisadditional material at the periphery may be provided purely byelectrolytic deposition.

The method described above produces an open weave in the disc, and thismay in itself be sufficiently strong to withstand the stresses producedin operation.

However, it may be necessary to fill in the disc, apart from the centralaperture, and this may be done with a lightweight material, for example,a foamed ceramic in the case of high temperature discs, or resininjection in the case of lower temperature discs.

Filling in the weave by these methods would in any case provide the discwith greater axial stiffness and prevent flutter of the fiber portionswithin the disc.

A plurality of aerofoil shaped blades are attached to the disc at itsouter periphery in order to complete the rotor assembly. The blades mayof course be made of conventional materials or may be made of fiberreinforced resins or metals. In the case ofa fiber reinforced resin discthe blades may be bonded on with a resin bond, and in the case of a discmade from metal coated fibers with a strengthened periphery the bladesmay be welded to the periphery.

The blades may, if desired, be made integral with the disc in variousways as shown in FIGS. 4 to 6.

In FIG. 4 one method is illustrated wherein during the continuouswinding of the disc, an additional radial movement is superimposed onthe weaving motion everytime a point on the circumference of the disc isreached thus forming a radial loop 40, the radii of the loops beingarranged to suit the diameters of the fibers to avoid stressconcentrations.

The whole blade disc assembly may then be formed by assembling aplurality of discs and blade segments 41 in axial juxtaposition andinterposing a plurality of layers 42 of circumferentially wound fibersat the outer periphery of the disc. The aerofoil shape for the blade maybe finally produced by any of a plurality of methods, for example,forming a rough shape of removable expendable material around the fibersof the blade and coating their form with refractory metals or ceramicsby spraying or vacuum deposition. In one method as above an electricallyconducting wax former is made on which the fibers are positioned and thewhole assembly is electroplated with a metal or metal alloy, and the waxis finally melted out leaving a hollow reinforced metal section in therequired shape of the blade.

In the embodiment shown in FIG. 4 the ends of the loops may be cut andthe individual fibers bent over to project circumferentially from eitherside of the blade and thus form a shroud on the blade tip.

Alternatively as more layers are wound onto the disc, the radiallyextending fibers may be cut short at different radial lengths to providea tapering blade section.

An alternative method of making a blade with a shroud is shown in FIGS.5 and 6. In these embodiments the fiber 50 which forms a woven disc iscaused to move radially from the periphery of the disc to lie along oneflank 51 of one blade and then to move circumferentially around the discby one blade pitch and finally to move radially inwards towards thecircumference of the disc to lie along one flank 52 of the next adjacentblade before traversing across the disc to the periphery on the oppositeside of the disc. By this means a thin lamina section comprising a thindisc, having a plurality of portions of blade profile spaced around itscircumference each having a shroud integral with the next adjacent bladeprofile section may be formed. These lamina sections may be built upwith interposed layers of circumferential fibers 53 at the disc rim intoa complete blade disc assembly. Finally the whole blade disc assemblywith its shroud may be resin plated or electro-plated to form thefinished article as seen in FIG. 6.

The invention has been described referring to a single fiber element butit is clear that a plurality of fibers may be put together to form abundle which itself is coated and the same processes would apply usingthe bundle of fibers.

The fibers to be used are ideally carboniferous fibers but again otherfibers such as silica fibers or boron fibers with suitable coatings maybe used.

The blades maybe made hollow and suitable provision made forfeeding'cooling air from the disc to the blades.

In the case of separately made blades and rotors the blades may be madefrom fiber reinforced materials and may be made by any of the processesdescribed in our co-pending US. application Ser. No. 685,434 filed Nov.24, 1967 and now U.S. Pat. No. 3,532,438 issued Oct. 6, 1970, andBritish application Ser. No. 16874/67.

What we claim is:

1. Apparatus for winding one or more fibers under tension onto a former,comprising:

an epicyclic system having (a) an annulus wheel means and (b) at leastone planet wheel means which can be rolled about a circumference of saidannulus wheel means to define an epicycloid path of travel for everypoint on each of said planet wheel means except for a pointcorresponding to the axis of rotation for the planet wheel means,driving means for rotating each of said planet wheel means in its owncenter axis to thereby roll each planet wheel means about thecircumference of said annulus wheel means, and

guide means operatively associated with one of said planet wheel meansfor guiding one or more fibers from a source ofsupply onto a former,said guide means being arranged so that its end nearer said formerfollows a substantially epicycloid motion dictated by the planet wheel.means rolling about the circumference of said annulus wheel means,thereby causing said one or more fibers to be drawn under tension ontosaid former.

2. The apparatus of claim 1 wherein said annulus wheel means and saidplanet wheel means comprise gear members which maintain a meshingengagement during rotation of said planet wheel means by said drivingmeans.

3. The apparatus of claim 1 wherein said epicyclic system includes twoplanet wheel means which are carried for rotation on opposite ends of anarm means so that the two planet wheel means contact diametricallyopposite sides of said annulus wheel means during a rolling of theplanet wheel means about the circumference of the annulus wheel means,and wherein said driving means is connected to said arm means forimparting rotation to the planet wheel means.

4. An apparatus according to claim 1 in which the former has a pluralityof circumferentially arranged projections around which the fibers pass.

5. An apparatus according to claim 1 in which the former is rovided withgrooves for receivin said one or more ibers, the pattern of the groovesemg substantially epicycloid.

1. Apparatus for winding one or more fibers under tension onto a former,comprising: an epicyclic system haVing (a) an annulus wheel means and(b) at least one planet wheel means which can be rolled about acircumference of said annulus wheel means to define an epicycloid pathof travel for every point on each of said planet wheel means except fora point corresponding to the axis of rotation for the planet wheelmeans, driving means for rotating each of said planet wheel means in itsown center axis to thereby roll each planet wheel means about thecircumference of said annulus wheel means, and guide means operativelyassociated with one of said planet wheel means for guiding one or morefibers from a source of supply onto a former, said guide means beingarranged so that its end nearer said former follows a substantiallyepicycloid motion dictated by the planet wheel means rolling about thecircumference of said annulus wheel means, thereby causing said one ormore fibers to be drawn under tension onto said former.
 1. Apparatus forwinding one or more fibers under tension onto a former, comprising: anepicyclic system haVing (a) an annulus wheel means and (b) at least oneplanet wheel means which can be rolled about a circumference of saidannulus wheel means to define an epicycloid path of travel for everypoint on each of said planet wheel means except for a pointcorresponding to the axis of rotation for the planet wheel means,driving means for rotating each of said planet wheel means in its owncenter axis to thereby roll each planet wheel means about thecircumference of said annulus wheel means, and guide means operativelyassociated with one of said planet wheel means for guiding one or morefibers from a source of supply onto a former, said guide means beingarranged so that its end nearer said former follows a substantiallyepicycloid motion dictated by the planet wheel means rolling about thecircumference of said annulus wheel means, thereby causing said one ormore fibers to be drawn under tension onto said former.
 2. The apparatusof claim 1 wherein said annulus wheel means and said planet wheel meanscomprise gear members which maintain a meshing engagement duringrotation of said planet wheel means by said driving means.
 3. Theapparatus of claim 1 wherein said epicyclic system includes two planetwheel means which are carried for rotation on opposite ends of an armmeans so that the two planet wheel means contact diametrically oppositesides of said annulus wheel means during a rolling of the planet wheelmeans about the circumference of the annulus wheel means, and whereinsaid driving means is connected to said arm means for imparting rotationto the planet wheel means.
 4. An apparatus according to claim 1 in whichthe former has a plurality of circumferentially arranged projectionsaround which the fibers pass.